What is RHD Boost?

RHD Boost is a national project involving the roll out of a new naturally occurring overseas strain of rabbit calicivirus called RHDV1 K5. Itwill boost existing biological control agents that are already out in the environment. RHDV1 K5 is not asilver bullet and we need land managers to be vigilant in not taking their foot off thepedal when it comes to their regular rabbit control.

Rabbits are Australia’s most destructive agricultural pest animal, costing $200 million in lost agricultural production every year. Rabbits are environmental vandals. Less than one rabbit per hectare is enough to stop the growth of some native species and negatively affect biodiversity leading to further loss of native species of plants and animals.

RHD Boost is about fine tuning and enhancing the existing strain of calicivirus – it is an evolution rather than a revolution. This is a national experiment to better control rabbits, particularly in areas where the current Czech strain of RHDV (RHDV1 v351) has not had much success.

RHDV1 K5 is not a new virus; it is a Korean variant of the existing virus already widespread in Australia. The RHD Boost evaluation project found that RHDV1 K5 should work better in the cool-wet regions of Australia where the current variant has not been so successful. RHDV1 K5 was selected out of 38 candidate variants because it can overcome the protective effects of a benign calicivirus which naturally occurs in Australia’s rabbit population. RHDV1 K5 is a naturally occurring variant of RHDV. The virus has not been altered by humans in any way.

RHDV1 K5 kills more rabbits and is a faster death than the current variant of RHDV. This leads to improved animal welfare and humaneness outcomes as well as helping to lessen the impacts of rabbits on biodiversity and production.

It is unlikely that RHDV1 K5 will achieve the population reductions that the 1996 calicivirus release initially did, as it is not being released into a naïve population. Knockdowns are expected to be on average around 10–15% (ranging from between 0–40%). It is important that RHDV1 K5 is used as part of an integrated multi-technique rabbit management program.

Rabbit biocontrol can be beneficial if applied as part of an integrated and complementary pest management approach. An improved biological control agent in conjunction with a community-led response, using best practice rabbit management principles, is an opportunity to mitigate this damage. Rabbits don’t stop at fences and if we are to make any serious dent in the population a coordinated community-led response will be needed. RHDV1 K5 offers a new opportunity to begin a conversation with neighbours with the aim of integrated best practice rabbit control at a landscape scale. Land management groups are encouraged to get their communities involved in rabbit management and monitoring for the disease.

The RHDV1 K5 release has been approved and a trial release at over 600 sites across Australia is proposed for autumn 2017.